JP3483670B2 - Display device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an AV (AudioVisua).
l) The present invention relates to a display device used for equipment and OA (Office Automation) equipment.

[0002]

2. Description of the Related Art In recent years, there has been a demand for a home-use television used as an AV device and a display device used for an OA device to be lightweight, thin, low in power consumption, high in definition and large in screen size. It is rising. Therefore, CRT (Cathode
-RayTube) display, LCD (LiquidCrystalDispla)
y), plasma display, EL (ElectroLuminescen
t) Displays, LED (Light Emitting Diode) displays, and other display devices have also been developed to improve the above, and some of them are being put to practical use.

In particular, the position of television as entertainment is increasing at home. Considering the current sales situation of TVs, although the price per inch is decreasing, it is gradually shifting to larger TVs. Has become an essential requirement.

Similarly, in the business field, it is easy to handle, and clear images can be obtained not only in still images but also in moving images. Further, it can be applied to presentations using a computer and has a high visual effect. The display device as described above has been used also from the viewpoint that it can be obtained, and further increase in size is expected.

Among them, the liquid crystal display device can be remarkably thin in the depth direction, that is, the thickness, as compared with other display devices, so that the liquid crystal display device is lightweight and can be easily installed in a narrow space, and at the same time consumes less power. Since it is easy to realize full-color, it has been used in various fields in recent years, and expectations for a larger screen than other display devices are increasing.

In the above-mentioned large screen, when the resolution per one screen is the same, the rough image is conspicuous. Therefore, it is necessary to improve the image resolution as well as the image quality of the video source. In a liquid crystal display device, a large number of display elements are integrally formed at the same time and an image is formed by independently controllable display elements. Improving the resolution is nothing but increasing the number of the display elements.

However, the reduction of the defect rate of each display element alone in the manufacturing process is almost at the present level, and a dramatic progress cannot be expected. Therefore, increasing the number of display elements with the increase in screen size of the liquid crystal display device deteriorates the manufacturing yield of the entire display device at an accelerating rate. As a result, the liquid crystal display device with a large screen and high image quality is obtained. Was difficult to increase the production amount and became very expensive.

In order to solve the above problem, as shown in FIG. 2 of this embodiment, a liquid crystal display of a so-called multi-panel display system in which a plurality of liquid crystal display devices are connected to display one image. A method of realizing a large screen using a device has been adopted. By using such a method, even if the defect rate of a single display element is equal, the defect rate of the entire display device is dispersed, it is possible to improve the yield of the liquid crystal display device as a whole,
It is possible to suppress an increase in cost per unit area and obtain a liquid crystal display device having a large screen and high image quality at low cost.

[0009]

In forming the above-mentioned multi-display type liquid crystal display device, a reinforcing substrate 3 is used in order to connect the liquid crystal panels to each other, as shown in FIG. 12 (a), for example. In addition, multiple liquid crystal panels 2.2
By adhering the two adjacent to each other, a liquid crystal display device having a larger area can be formed.

However, when a plurality of liquid crystal panels 2 are joined together to form the liquid crystal display device 1 described above, the end surface portion 2c of the liquid crystal panel 2 is in contact with a medium having a different refractive index (for example, air). Then, refraction of light occurs there. In addition, if the end surface portion 2c becomes rough during processing, light refraction /
Scattering occurs. These cause the connection between the liquid crystal panels 2 to be conspicuous. Therefore, the refractive index of the adhesive used to bond the reinforcing substrate 3 and the liquid crystal panel 2 to each other is equal to the refractive index of the adhesive used to connect the liquid crystal panels 2 and 2 to each other. It is preferable that the refractive index is substantially equal to the refractive index of the reinforcing substrate 3 or the substrate that constitutes the liquid crystal panel 2. This makes it possible to avoid the refraction and scattering of light as described above.

However, as shown in FIG. 2B in the above-mentioned form, when the adhesive 9 is used, the liquid crystal panel 2
A crack 9a is generated along the vicinity of the edge 2 of FIG. This is the edge 2a of the liquid crystal panel 2.2 (see FIG. 12).
In the vicinity of (a), stress concentration due to curing shrinkage of the adhesive 9 occurs, so that the crack 9a is caused to grow or grow by a slight impact or the like. When light passes through such a crack 9a, it is scattered and causes a connection portion between the liquid crystal panels 2 and 2 to be conspicuous. Further, due to the above-mentioned curing shrinkage, partial peeling 9b may occur between the end surface portion 2c of the liquid crystal panel 2.2 and the adhesive 9 and the above light scattering may occur. . On the other hand, if the surface accuracy of the end face portion 2c is rough, the adhesive 9 does not sufficiently penetrate into the irregularities of the end face portion 2c, so that a small amount of space exists between the end face portion 2c of the liquid crystal panel 2 and the adhesive agent 9. Bubbles may remain, and in this case also light scattering will occur.

In other words, in order to obtain a natural large screen image, the generation of light scattering that makes the joint between the liquid crystal panels 2 stand out by preventing the above-mentioned cracks 9a, peeling 9b, and bubbles from occurring. Need to be blocked.

It is an object of the present invention to provide a display device having a large screen by connecting a plurality of panels as described above, which realizes a natural large screen without causing light scattering at a joint between the panels. To provide.

[0014]

A display device according to claim 1 of the present invention is a display device having a plurality of display panels each of which is composed of a pair of substrates which are peripherally sealed, and the end faces of the display panels are connected adjacent to each other. In a multi-panel display device that displays a screen, the plurality of display panels are adjacently connected to each other by using an adhesive that causes volume shrinkage during curing to reinforce the connection portion.
Reinforcing board is attached to one side of the display panel
There Rutotomoni, reinforcement at the connection end face of the display panel
The edge portion on the plate side is characterized in that a chamfered portion is provided to relieve stress concentration due to curing shrinkage of the adhesive. According to the above configuration, even if internal stress occurs due to curing shrinkage of the adhesive in the connection portion between the display panels, stress concentration is caused by the chamfered portion formed at the edge portion on the reinforcing substrate side of the connection end surface of the display panel. Since it is relieved, the maximum value of the internal stress becomes smaller than the intermolecular bonding force of the cured adhesive, and it is possible to prevent the occurrence of cracks starting from the edge portion. Accordingly, it is possible to provide a display device that realizes a natural large screen without causing light scattering at the joint between the panels.

A display device according to a second aspect is a multi-panel display in which a plurality of display panels composed of a pair of substrates sealed in the periphery are connected to each other so that end faces of the display panels are adjacently connected to each other. In the device, the plurality of display panels are adjacently connected to each other using an adhesive that causes volume contraction during curing, and a reinforcing substrate that reinforces the connection portion is bonded to one surface of the display panel, and after curing. Song
If an adhesive with a flexural modulus of less than 4000 kgf / cm2 is used
It is characterized by being . According to the configuration of the above Symbol,
When the flexural modulus after curing of the adhesive is 4000 kgf / cm ² or less, the maximum value of the internal stress acting in the adhesive is greater than the intermolecular bonding force of the cured adhesive even if the curing shrinkage amount of the adhesive is the same. Since it becomes smaller, the occurrence of cracks in the adhesive at the edge portion can be prevented, and the internal stress becomes smaller than the adhesive force between the adhesive and the display panel, so that the occurrence of peeling can be prevented. Accordingly, it is possible to provide a display device that realizes a natural large screen without causing light scattering at the joint between the panels.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] The following will describe one embodiment of the present invention with reference to FIGS. 1 to 4. As shown in FIG.
The liquid crystal display device 1 according to the present embodiment is a direct-viewing type liquid crystal display device, and the active matrix liquid crystal panels 2 and 2 are provided on the lower surface of the reinforcing substrate 3 having a size that covers the entire display screen of the liquid crystal display device 1. And the polarizing plates 8 and 8 to be described later are provided above and below so as to sandwich the reinforcing substrate 3 and the liquid crystal panel 2.2, and a cold cathode tube or the like not shown on the lower side of the liquid crystal panel 2.2 in the figure. The backlight and a driver for controlling the displayed image signal. By controlling the liquid crystal panels 2 and 2 according to image information and modulating the light of the backlight, the image information input to the liquid crystal panel 2 can be recognized.

The structure of the liquid crystal panel 2 is, as shown in FIG. 3, an active matrix type liquid crystal panel structure using well-known matrix-shaped active elements. That is, in order to eliminate the crosstalk between the scanning electrodes that occurs in the simple matrix, each pixel is provided with a switch that completely cuts unrelated signals when not selected. This switch is called an active element, and this system is called an active matrix type. As the active element, a 2-terminal element called a diode or a 3-terminal element called a transistor is used.

On the first substrate 10 made of a glass substrate, the scanning electrodes 14, the data electrodes 13, and the TFTs 16 ... (ThinFilmTransi) arranged at the intersections of these electrodes.
stor), pixel electrodes 15 ... TFT16
Is a field effect transistor using a semiconductor thin film such as amorphous silicon (a-Si: H) or polycrystalline silicon (p-Si), and controls the supply of the image signal to the pixel electrode 15. The pixel electrode 15 is made of ITO (indium tin oxide) when used as a transmissive display device.
When used as a reflective display device, it is formed of a reflective conductive film such as Al.

On the other hand, the common electrode 12 is formed on the second substrate 11.
Are formed. When performing color display, R (red), G (green), B corresponding to each pixel electrode
A (blue) color filter 4 ... And a black matrix 5 for separating each pixel are formed. The black matrix 5 is provided so as to block light from entering the gaps between the pixel electrodes 15 ... And the TFT area, and is formed so as to cover the periphery of each pixel electrode 15. This is because if light is transmitted to areas other than the pixel electrodes 15 ..., the quality of the black display state is deteriorated and the contrast is lowered, and when light is incident on the TFT 16, a leak current due to photoexcitation occurs in the TFT channel, This is because the display quality is degraded. The black matrix 5 may be provided on the first substrate 10 side instead of the second substrate 11 side.

To form the liquid crystal panel 2, the first substrate 10 and the second substrate 11 are formed on the pixel electrode 15 and the common electrode 1.
2 and the liquid crystal 7 are sealed between the first substrate 10 and the second substrate 11 with the sealing material 6 shown in FIG. Then, as shown in the figure, when the liquid crystal panels 2 are joined together, the connecting portion between the liquid crystal panels 2 is filled with an adhesive 9 which serves as a refractive index adjusting material. If the adhesive 9 does not have the same refractive index as that of the liquid crystal panel 2, the unevenness of the end faces of the first substrate 10 and the second substrate 11 forming the liquid crystal panel 2 scatters light, which may cause the connection portion to stand out. Become. The adhesive 9 is also preferably used when the joined liquid crystal panels 2 and the reinforcing substrate 3 are attached to each other. Also in this case, the reinforcing substrate 3 and the second substrate 11
This is because if light is reflected at the interface between the and, it will cause a reduction in the contrast during display.

In this embodiment, a glass substrate (Corning 7059) having a refractive index of 1.53 is used as the material for the first substrate 10 and the second substrate 11, so that the adhesive 9 has a refractive index of It is necessary to use 1.53 material. For example, an ultraviolet curable resin having a double bond site such as acrylic or ene / thiol, in which the double bond is cleaved by irradiation with ultraviolet light and polymerization proceeds, and the refractive index after curing is 1.53. It is recommended to use a resin.

The liquid crystal panel 2 joined in this way
To cover almost all of the front and back of each,
The liquid crystal display device 1 is formed by arranging the polarizing plates 8 and 8 in directions in which their polarization axes are orthogonal to each other. In general, a direct-viewing type liquid crystal display device is provided with a backlight such as a cold cathode tube as described above, and a liquid crystal panel placed in front of the backlight causes the light of the backlight to be emitted in accordance with image information. The image information that has been modulated and input to the liquid crystal panel can be recognized. In the liquid crystal display device 1 of the present embodiment, the polarizing plate 8 is installed on substantially the entire surface of the liquid crystal display device 1 configured by joining a plurality of liquid crystal panels 2 as described above, and the polarizing plates 8 and 8 Are installed on the front and back sides of the liquid crystal display device 1 in a direction in which their polarization axes are orthogonal to each other, so light leakage from the connecting portion between the liquid crystal panels 2 is normally black in the crossed Nicols state of the polarizing plate. Since it is present, the above-mentioned connecting portion is inconspicuous.

FIG. 1 shows an enlarged view of a connecting portion of the liquid crystal panels 2.2 of the liquid crystal display device of the present invention. The end surfaces of the two liquid crystal panels 2.2 are connected via an adhesive 9. At the same time, the reinforcing substrate 3 and the liquid crystal panels 2 and 2 are similarly bonded together via the adhesive 9. The adhesive 9 used for bonding the reinforcing substrate 3 and the liquid crystal panel 2 is an ultraviolet curable adhesive, which is cured by irradiating the adhesive 9 in a fluid state with ultraviolet rays. The tensile stress caused by the shrinkage of 5% to 10% caused by the adhesive 9
To work within. For example, if the edge 2a of the conventional example shown in FIG. 12 (a) is left in the cut-out shape, stress concentration occurs near the edge 2a, resulting in crack 9a. . Above crack 9
The light transmitted through a is scattered, and even if the polarizing plate 8 is provided, the light that matches the polarization direction of the polarizing plate 8 leaks upward and makes the connection between the liquid crystal panels 2 and 2 stand out. However, it has been an obstacle in promoting the multi-panel display of liquid crystal display devices.

Therefore, as shown in FIG. 1, an arcuate chamfered portion 2b is formed at the edge portion of the connection end face of the liquid crystal panel 2 used in this embodiment. As a result, the internal stress of the adhesive 9 is relieved over the entire chamfered portion 2b, so that the generation of the crack 9a as shown in FIG. 12B can be prevented. In the present embodiment, the chamfered portion 2b has an arc shape, and the radius of the chamfered portion 2b is 0.3 mm. The chamfered portion 2b having an arc shape is formed by, for example, rotating a grindstone 18 having a curved portion to scrape the edge portion of the liquid crystal panel 2 as shown in FIG. In the above method, first, rough grinding is performed using a grindstone with a grain size of # 300 to # 500,
Furthermore, chamfered portion 2b with less unevenness can be obtained by performing two-stage grinding such as finishing using a grindstone of grain size # 800 to # 1600. The radius of the arcuate chamfered portion 2b may be optimally set according to the thickness of the liquid crystal panel 2 and the installation conditions of the liquid crystal display device 1, but the shape of the chamfered portion 2b is limited to the arcuate shape. Instead of one, it may be processed into another shape that avoids stress concentration.

As a result, it was possible to obtain a liquid crystal display device in which light was not scattered and the connection between liquid crystal panels was inconspicuous.

[Second Embodiment] Another embodiment of the present invention will be described below with reference to FIGS. For convenience of explanation, members having the same functions as those shown in the drawings of the first embodiment will be designated by the same reference numerals, and the description thereof will be omitted.

FIG. 5 is a layout view of the liquid crystal panels 2 and 2 when laminated on a reinforcing substrate 3 not shown. As shown in FIG. 5A, each liquid crystal panel 2 has an image on one side. It is divided along the dividing lines 17 in the vicinity of the end of the display area, and is attached on the reinforcing substrate 3 so as to join the divided portions. As shown in FIG. 3B, the connection width D generated when the liquid crystal panels 2 are joined together is normally smaller than the line width a of the black matrix 5 required for one pixel. Aligned. The connection width D is the black matrix 5
If the line width a is too large, the pixel pitch of the entire screen is disturbed at the connection part of the liquid crystal panels 2 ..., and the observer feels uncomfortable.

Therefore, for the division of the liquid crystal panel 2, a high degree of division position accuracy and division surface finishing accuracy are required. If the dividing lines 17, 17 of the liquid crystal panel 2 are distorted or if the liquid crystal panel 2 has unevenness of several hundreds of μm, a further gap will be generated when the liquid crystal panels 2 are joined together. However, a general method of dividing the liquid crystal panel 2 by scribing cannot avoid the distortion of the cross section of about several hundreds of μm. A cutting method using a dicing machine is suitable for obtaining high cutting position accuracy and cutting surface finishing accuracy. If a dicing device is used, even if the production speed during mass production is taken into consideration, the cutting position accuracy of the end face on the connection side is 50 μm or less, and the cut surface finishing accuracy is 5 μm.
It can be suppressed to m or less. Note that, as shown in FIG. 6, what is referred to as the dividing position accuracy in the above is the maximum value A of the deviation of the actual dividing line with respect to the designed dividing line, and is also referred to as the dividing surface finishing accuracy. Is
It is the maximum height B in the surface roughness on the end face shown in the enlarged circle in the figure.

In this way, the connection width D is set to the line width a of the black matrix 5 or less, so that the pixel pitch of the entire liquid crystal display device 1 can be made uniform.

However, when the adhesive 9 is used to join the end faces of the liquid crystal panel 2 as described above, it is necessary to pay attention to the curing shrinkage of the adhesive 9. In other words, due to the stress concentration of the internal stress generated by the curing shrinkage, the adhesive 9 on the edge 2a of the liquid crystal panel 2 as shown in FIG.
Crack 9a or end face portion 2c as shown in FIG. 12 (b)
There is a possibility that a peeling portion 9b may occur between the adhesive 9 and the adhesive.

Therefore, the crack 9a and the peeling portion 9b are formed.
Think of preventive measures. For example, since the internal stress is associated with the curing shrinkage of the adhesive 9, if the volume of the adhesive 9 used is made smaller, the absolute value of the volume shrinkage becomes smaller. Thereby, the internal stress generated in the adhesive 9 at the time of curing contraction can be reduced. The cracks and peeling described above occur because the flexural modulus of elasticity of the commonly used adhesive 9 during curing and contraction (hereinafter simply referred to as the elastic modulus) is large, that is, the rigidity is high. Therefore, if the adhesive 9 having a small elastic modulus is used, it is possible to cancel the influence of the curing shrinkage.

Based on the above idea, a plurality of test pieces 19 shown in FIG. 7 were produced and the state of crack generation was observed. The test piece 19 is a glass plate 20 (width 60 mm x depth 100 mm x thickness 2.8 mm) imitating a reinforcing substrate in a liquid crystal display device, and glass plates 21 and 21 imitating a liquid crystal panel.
(Width 30mm x depth 100mm x thickness 2.2mm) and adhesive 22
Using, the thickness of the adhesive 22 is set and bonded as in the actual liquid crystal display device. And the glass plate 21
The test piece 19 having various patterns was prepared by combining the resin 22 having various changes in the connection width D between 21 and various resins having different elastic moduli as the adhesive 22, and the number of cracks generated at the edge portion was observed. The results are shown in Fig. 8.

As can be seen from the figure, the elastic modulus is 4000
It can be seen that when a resin of kgf / cm ² or less is used as the adhesive 22, regardless of the connection width D, the number of cracks caused by the curing shrinkage of the adhesive 22 is significantly reduced. From this result, when a resin having an elastic modulus of 4000 kgf / cm ² or less is used as the adhesive 22, the internal stress caused by the strain due to the shrinkage hardening of the adhesive 22 is canceled by the elasticity of the adhesive 22, and the liquid crystal panel It is presumed that this is because the intermolecular attractive force between 2 and the adhesive 9 becomes smaller.

Further, in the test strip 19, even when the elastic modulus using a resin of 4000 kgf / cm ² or more (6000kgf / cm ² or more resins in the experiment) as an adhesive 22, regardless of the type of resin, the connection It can be seen that by setting the width D to be 50 μm or less, the number of cracks caused by the curing shrinkage of the adhesive 22 is remarkably reduced similarly to the above. That is, when the connection width D is set to 50 μm or less, the internal stress caused by the absolute reduction of the shrinkage amount does not depend on the characteristics such as the flexural modulus of the adhesive which are considered to be greatly related to the occurrence of cracks. It can be presumed that the maximum value of the stress becomes equal to or less than the intermolecular bonding force of the adhesive 22 due to the reduction of the value, and the number of cracks generated near the edge portion is suppressed to be low. At the same time, in the test piece 19, the adhesive 22
At the interface between the glass plate 21 and the glass plate 21, the conventional example shown in FIG.
The formation of the peeled portion 9b as shown in 2 (b) was not observed.

From the above results, in the liquid crystal display device 1 having the same structure, the elastic modulus of the resin used for the adhesive 9 is set to 4000 kgf / cm ² or less, or the connection width between the liquid crystal panels 2 and 2 is reduced. It is considered that by setting D to 50 μm or less as described above, it is possible to prevent cracks or peeling between the end surface portion 2c and the adhesive 9 that occur near the edge 2a. Further, when the connection width D between the liquid crystal panels 2 is set to 50 μm or less, as described above, cracks and peeling generated in the adhesive 9 filled in the connection portion can be reduced, and at the same time, light in the adhesive layer can be reduced. Since the influence of absorption and birefringence can be reduced, the display performance is improved.

Actually, the position of the dividing line 17 is set,
As a result of producing a liquid crystal display device 1 in which a connection width D between the liquid crystal panels 2 and 50 is 50 μm and a resin having an elastic modulus of 10000 kgf / cm ² is used as the adhesive 9, no crack or peeling is observed in the connection portion. The liquid crystal display device 1 was able to be made in which the connecting portion between the liquid crystal panels 2 and 2 was inconspicuous. Also,
Even when the liquid crystal display device 1 having a connection width D = 100 μm was manufactured using a resin having an elastic modulus of 2000 kgf / cm ² as the adhesive 9, no cracks or peeling at the edges were observed, and the liquid crystal panel 2 It was possible to obtain the liquid crystal display device 1 in which the connection part of 1 was inconspicuous.

Third Embodiment Another embodiment of the present invention will be described below with reference to FIGS. 9 and 10. For convenience of explanation, members having the same functions as those shown in the drawings of the second embodiment will be designated by the same reference numerals, and the description thereof will be omitted.

In the second embodiment, the connection width D is set to 5 in order to prevent cracks and peeling due to shrinkage hardening of the adhesive 9.
It has been described that 0 μm or less is sufficient. However, the adhesive used for connecting the liquid crystal panels 2 and 2 has a different refractive index depending on its composition, curing conditions and ambient temperature, so that the refractive index at the time of curing becomes equal to that of the liquid crystal panel 2. It is practically difficult to manage the value of 0.005 on the order of 0.005, and some variation occurs during mass production. As can be seen by comparing FIGS. 9 (a) and 9 (b), when the connection width between the liquid crystal panels 2 is large, not only the distortion of the image observed through the adhesive 9 becomes large, but also the tint Will also change. Therefore, FIG.
As shown in (b), the smaller the connection width D, the smaller the image distortion due to the effect of light absorption and birefringence in the adhesive layer, and the display performance can be improved.

However, in the above-mentioned dicing machine, when the work feeding speed is slowed down among the mesh of the blade for dividing, the number of revolutions, and the work feeding speed, the processing accuracy is improved but the processing capacity is greatly increased. On the other hand, if the mesh of the blade is made finer and rotated at high speed, the precision of the sectional surface finishing is improved, but the blurring of the blade is increased,
Since there is a trade-off relationship that the dividing position accuracy decreases, it is difficult to reduce the dividing position accuracy to less than 50 μm or less while maintaining the sectional surface finishing accuracy of 5 μm or less in the case of mass production.

Therefore, a step of polishing the connection side end surface 2c of the liquid crystal panel 2 with a grindstone is provided. As a result, the liquid crystal panel 2 can be manufactured without reducing the production amount of the liquid crystal panel 2.
The connection width D between the two can be further narrowed. After being divided by the dicing device described above, the end face of the liquid crystal panel 2 was polished to obtain a liquid crystal panel 2 having a dividing position accuracy of 10 μm or less. By using this liquid crystal panel 2, the connection width between the liquid crystal panels 2 can be reduced to 2
It could be set to 0 μm or less.

A plurality of liquid crystal panels 21 'having different dividing position accuracy are prepared by using the above-mentioned polishing process, and the test piece 1 as shown in FIG. 10 is prepared by using the liquid crystal panels 21'.
A plurality of 9'was produced and the visibility was evaluated by the difference in the connection width D. In addition, the test piece 19 'uses the adhesive material 22 and uses the reinforcing substrate 20' (width 580 mm x depth 440 mm x thickness 2.
8mm), the liquid crystal panel 21 '・ 2 with the same dividing position accuracy
1 '(width 290 mm x depth 440 mm x thickness 2.2 mm) is pasted together.

[0042]

[Table 1] As a result, when the connection width D is 20 μm or less, it is possible to obtain a liquid crystal display device having good visibility which is hardly affected by the variation in the refractive index of the adhesive. That is, if a liquid crystal panel with a dividing position accuracy of 10 μm or less is used, the connection width D is always 20 μm or less, and thus good visibility can always be obtained.

[Fourth Embodiment] Another embodiment of the present invention will be described below with reference to FIG. For convenience of explanation, the second embodiment described above is used.
The members having the same functions as the members shown in the drawing are attached with the same notations and an explanation thereof will be omitted.

As described above, in the division by the dicing device, when the liquid crystal panels 2 and 2 are connected by the adhesive 9, the adhesive 9 does not sufficiently penetrate into the unevenness of the dividing plane, and the liquid crystal panel There is a case in which minute air bubbles remain between the end surface portion 2c of 2 and the adhesive 9, and light is scattered by the air bubbles. It is considered that this is because the wettability between the adhesive 9 and the end face portion 2c is not sufficient with the sectional surface finishing accuracy of about 5 μm obtained by the dicing device.

Therefore, a liquid crystal panel 21 'having a different sectional surface finishing accuracy is obtained by using a polishing process using a grindstone as described above.
I prepared several. Then, a plurality of test pieces 19 ′ having the same shape as that shown in FIG. 10 were prepared, the connection portion was observed, and the air bubble entrainment property was evaluated. However, in the test piece 19 'used in the present embodiment, the connection width D between the liquid crystal panels 21' and 21 'is 100 .mu.m in order to facilitate the observation of bubbles.

[0046]

[Table 2] From the above results, it was found that the inclusion of bubbles was not observed when the sectional surface finishing accuracy was 2 μm or less.
As a result, it was possible to prevent the scattering of light due to the bubbles in the connection portion and obtain a natural image.

The polishing of the end faces of the glass plate 21 and the liquid crystal panel 21 'on the connection side, which is carried out in the second to fourth embodiments, is performed, for example, as shown in the processing example of the liquid crystal panel 2 of FIG. 2c may be scraped off by a rotating grindstone 23. As the grindstone 23, a # 800 grindstone is used, and the polishing rate 1 at the contact portion between the grindstone 23 and the end surface portion 2c is 1.
When polishing was carried out under the conditions of km / min and grindstone feed rate of 2 μm / step, the end face portion 2c having a cutting position accuracy of 10 μm or less and a cutting finished surface accuracy of 2 μm or less could be obtained. In addition, when the surface of the end surface portion 2c before polishing is rough, first, rough cutting is performed using a grindstone with a grain size of # 300 to # 500, and then finishing is performed using a grindstone with a grain size of # 800 to # 1600. As described above, by performing the two-step polishing, the end surface portion 2c having less unevenness can be obtained.

In each of the above embodiments, a multi-panel liquid crystal display device is shown in which a liquid crystal panel is connected to increase the screen size. However, this technique for increasing the screen size is not applied only to the liquid crystal panel. Instead, for example, in the sense that a large screen can be achieved by diverting a conventional size display manufacturing line, a plasma display or an EL (ElectroLuminesc)
(ent) display may be applied to a multi-panel display.

[0049]

As described above, in the display device according to the first aspect of the present invention, the plurality of display panels are adjacently connected to each other by using an adhesive that causes a volume shrinkage upon curing to reinforce the connection portion.
Reinforcing board is attached to one side of the display panel
There Rutotomoni, reinforcement at the connection end face of the display panel
The edge portion on the plate side is provided with a chamfered portion for relieving stress concentration due to curing shrinkage of the adhesive. The display device according to claim 2, wherein the plurality of display panels are adjacently connected to each other using an adhesive that causes volume contraction during curing, and a reinforcing substrate that reinforces the connection portion is attached to one surface of the display panel. And the flexural modulus after curing is 4000
This is a configuration in which an adhesive with a kgf / cm2 or less is used . Its Reyue, using any of the configurations according to the claims above, since no cracks or peeling occurs in the adhesive to fill the connecting portion of the display panel, the connecting portion of the liquid crystal panel is not conspicuous, excellent visibility This has the effect of providing a large-screen display device. Furthermore, by combining the above configurations, further improvement of the above effects can be expected.

[Brief description of drawings]

FIG. 1 is a sectional perspective view showing a connecting portion between liquid crystal panels of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a schematic configuration of a liquid crystal display device according to an embodiment of the present invention.

FIG. 3 is a perspective view showing a configuration pattern of a liquid crystal panel provided in the liquid crystal display device.

FIG. 4 is a diagram showing an example of a method for forming a chamfered portion of a liquid crystal panel.

FIG. 5 is a diagram showing an arrangement of liquid crystal panels, and FIG.
FIG. 4A is a plan view showing a cut position at a connection portion between a single liquid crystal panel and a liquid crystal panel, and FIG. 6B is a plan view showing an arrangement of the liquid crystal panel after cutting.

FIG. 6 is a perspective view of a liquid crystal panel for explaining the dividing position accuracy and the dividing surface finishing accuracy.

FIG. 7 is a perspective view showing the shape of a test piece according to another embodiment of the present invention.

FIG. 8 is a graph showing the results of measuring the number of cracks generated at the edge portion using a plurality of adhesives having different flexural moduli after curing, and the horizontal axis is the connection width D between the test pieces. The vertical axis represents the incidence of cracks made dimensionless by the maximum number of cracks.

FIG. 9 is an explanatory diagram showing a deformation degree due to a difference in connection width of an image transmitted through a connection portion.

FIG. 10 is a perspective view showing the shape of a test piece according to another embodiment of the present invention.

FIG. 11 is a schematic view showing a method of processing an end surface portion of a liquid crystal panel.

FIG. 12 is a sectional perspective view showing a connecting portion between liquid crystal panels of a liquid crystal display device using a conventional multi-panel display system.

[Explanation of symbols]

1 Liquid crystal display device (display device) 2 Liquid crystal panel (display panel) 2a Edge (edge part) 2b Chamfer 2c End face part (connection end face) 9 Adhesive D connection width (spacing)

   ─────────────────────────────────────────────────── ─── Continued front page       (56) References JP-A-52-108836 (JP, A)                 JP 4-75023 (JP, A)                 JP-A-7-98450 (JP, A)                 JP-A-56-167183 (JP, A)                 JP 57-136616 (JP, A)                 JP 61-262783 (JP, A)                 Actually open 64-3824 (JP, U)

Claims (2)

(57) [Claims] 1. A multi-panel display device that performs a large-screen display by connecting a plurality of display panels, each of which is composed of a pair of substrates sealed in the periphery, with end faces of the display panels adjacent to each other. Panels are connected adjacent to each other using an adhesive that causes volume shrinkage during curing, and a reinforcing substrate that reinforces the connection part,
Rutotomoni been adhered to one surface of the display panel, and characterized in that the edge portion of the reinforcing substrate side of the connection end face of the display panel, provided with a chamfer for reducing the stress concentration due to curing shrinkage of the adhesive Display device. 2. A multi-panel display device for performing a large-screen display by connecting a plurality of display panels composed of a pair of peripherally sealed substrates to each other by connecting the end faces of the display panels to each other. Panels are connected adjacent to each other using an adhesive that causes volume shrinkage during curing, and a reinforcing substrate that reinforces the connection part,
Adhered to one surface of the display panel and having a flexural modulus after curing of 4000 kgf / cm2 or less
A display device characterized in that an agent is used .